[masraum]

Some of the tech that they came up with to grow things was amazing. Up in the mountains where it got cold at night, they had crops planted with lots of water like canals or moats around and through the crops. At night, the water kept the crops warm.
In the Amazon, the soil is crap, but they managed to "treat" the soil in ways that made it super fertile for crops. Then, of course, there were the amazing buildings that were built all through the area. Stuff that is astounding today.

So often modern man looks back at "primitive" man and thinks "they must have been super primitive, but they managed some amazing feats that baffle us today.